Field of the Invention
The present invention relates to a zoom control apparatus and a zoom control method for controlling a zoom operation.
Description of the Related Art
Conventionally, there have been known imaging apparatuses having both the function of performing an optical variable magnification (optical zoom) by driving a zoom lens and the function of performing an electronic variable magnification (electronic zoom) by enlarging a part of a captured image. There have also been known imaging apparatuses having an automatic zoom function, which automatically changes a zoom position according to information detected from an object (subject).
Japanese Patent Application Laid-Open No. 2012-95019 discusses the configuration of a camera equipped with an automatic zoom function which keeps the size of an object image constant. Japanese Patent Application Laid-Open No. 2012-95019 also discusses a method in which the user, when using the automatic zoom function, is allowed to select a composition pattern from among a plurality of options, such as “face close-up”, “upper-body close-up”, and “whole body”. The automatic zoom control, which maintains the size of an object image, determines the size of an object image, which serves as a benchmark for zoom control, based on the selected composition pattern. For example, when “whole body” is selected, a zoom operation is performed in such a way as to cause the whole-body image of a person serving as an object to be set in a shooting image plane.
Furthermore, Japanese Patent Application Laid-Open No. 2011-259285 discusses the setting of a zoom speed that can be set to make an object unlikely to move to outside the frame in an automatic zoom function. Japanese Patent Application Laid-Open No. 2011-259285 also discusses decreasing the zoom speed in a case where the distance from the center of an image plane to an object within the image plane is long or in a case where the size of an object within the image plane is large.
However, in the case of Japanese Patent Application Laid-Open No. 2011-259285, only the position of an object within the image plane is taken into consideration in the setting of a zoom speed. Therefore, in the method for setting a zoom speed discussed in Japanese Patent Application Laid-Open No. 2011-259285, in a case where the automatic zoom is performed based on a composition as discussed in Japanese Patent Application Laid-Open No. 2012-95019, an object may become likely to move to outside the frame depending on the selected composition.